6E–25
3.2L ENGINE DRIVEABILITY AND EMISSIONS
This would be the following flash, sequence: “flash,
pause, flash-flash, long pause, flash, pause, flash-flash,
long pause, flash, pause, flash-flash”. DTC 12 indicates
that the ECM’s diagnostic system is operating. If DTC 12
is not indicated, a problem is present within the diagnostic
system itself, and should be addressed by consulting the
appropriate diagnostic chart in DRIVEABILITY AND
EMISSIONS.
Following the output of DTC 12, the “Check Engine”MIL
will indicate a DTC three times if a DTC is present, or it will
simply continue to output DTC12. If more than one DTC
three has been stored in the ECM’s memory, the DTC(s)
will be output from the lowest to the highest, with each
DTC being displayed three times.
Reading Diagnostic Trouble Codes Using
a TECH 2
The procedure for reading diagnostic trouble code(s) is to
used a diagnostic Tech 2. When reading DTC(s), follow
instructions supplied by Tech 2 manufacturer.
For the 1998 model year, Isuzu dealer service
departments will continue to use Tech 2.
Clearing Diagnostic Trouble Codes
IMPORTANT:
Do not clear DTCs unless directed to do
so by the service information provided for each diagnostic
procedure. When DTCs are cleared, the Freeze Frame
and Failure Record data which may help diagnose an
intermittent fault will also be erased from memory.
If the fault that caused the DTC to be stored into memory
has been corrected, the Diagnostic Executive will begin to
count the “warm-up” cycles with no further faults
detected, the DTC will automatically be cleared from the
ECM memory.
To clear Diagnostic Trouble Codes (DTCs), use the Tech
2 “clear DTCs” or “clear information” function. When
clearing DTCs follow instructions supplied by the Tech 2
manufacturer.
When a Tech 2 is not available, DTCs can also be cleared
by disconnecting
one of the following sources for at least
thirty (30) seconds.
NOTE: To prevent system damage, the ignition key must
be “OFF” when disconnecting or reconnecting battery
power.
D
The power source to the control module. Examples:
fuse, pigtail at battery ECM connectors etc.
D
The negative battery cable. (Disconnecting the
negative battery cable will result in the loss of other
on-board memory data, such as preset radio tuning).
On-Board Diagnosis (Self-Diagnosis)
1. The Engine Control Module (ECM) conducts a
self-test of most of the wiring and components in the
system each time the key is turned to ON, and can
detect faults in the system while the key is ON. If a
fault is detected, the ECM will store a trouble code in
memory and flash the CHECK ENGINE indicator to
alert the driver.
2. The Diagnostic Trouble Codes (DTC) can be
displayed by shorting together terminals and the Data
Link Connector (DLC) located below Instrument
Panel of drivers side.
The CHECK ENGINE indicator will flash DTC 12
three times, followed by any DTC.If several DTC are
stored, each DTC will be displayed three times. The
DTC will be displayed in numerical order. The DTC
display will continue as long as the DLC is shorted.
Some DTC can cause other DTC to be stored, It is
important to diagnose and repair the lowest
numbered DTC first before going on to the higher
numbered DTC.